scholarly journals The Influence of Rib Configuration on Bond Strength Development between Steel and Concrete

2020 ◽  
Vol 6 (1) ◽  
pp. 193
Author(s):  
Sarvat Gull ◽  
Shoib B. Wani ◽  
Ishfaq Amin
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Mild Steel ◽  
Testing Machine ◽  
Frictional Resistance ◽  
High Yield ◽  
Strength Development ◽  
Quality Performance ◽  
Pull Out ◽  
Interface Bond Strength

 The bond strength between rebar and concrete is important for the quality performance of reinforced concrete structures. At the interface, bond strength development mainly depends on surface configuration. Different rib configuration improves the strength significantly in high yield rebars as compared to mild steel. This study examines the bond strength behavior of ordinary MS (Mild Steel) rebars, HYSD (High Yield Strength Deformed) parallel rib, and HYSD diamond rib rebars. Experimental analysis to obtain pull-out behavior of rebar in concrete was based on IS 2770 Part I – 1967: Reaffirmed 2007; Indian Standard Methods of Testing Bond in Reinforced Concrete.  Importantly, the concrete of M30 grade was used and a total of nine specimens were tested. The cubes of size 150mm x 150mm x 150mm were cast with centrally embedded rebar provided up to 20 mm from their bottom faces. Additionally, the pull-out test was conducted in 1000 kN capacity Universal Testing Machine. The usable bond strength values were calculated from the load at 0.025 mm free and 0.25 mm loaded end slips. The results showed that the usable bond strength value of HYSD diamond rib rebars is very large compared to MS and appreciably greater than HYSD parallel rib. Moreover, the usable bond strength of HYSD diamond rib rebars is 60.06% and 35.60 % greater than that of the MS rebars and HYSD parallel rib pattern rebars, respectively. The high frictional resistance developed in the bond strength test of HYSD diamond rib rebars because of the better mechanical interlocking. This was primarily due to the presence of a more frictional surface area of lugs. 

scholarly journals Bond Behaviour of Steel and Concrete with Pull-Out Test

2019 ◽  
Vol 9 (2) ◽  
pp. 3853-3857
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
Strength Development ◽  
Bond Behaviour ◽  
Concrete Mix Design ◽  
Pull Out ◽  
Universal Testing ◽  
Cement Compound ◽  
Compound Coating ◽  
Code Procedure

This experimental investigation presents the influence of rebar’s which has protecting coating, rested rebar and fresh rebar and there bond strength development between the steel and concrete. Pull-out experiment was conducted Universal Testing Machine (UTM) which has a capacity of 400 KN as per IS code procedure. The tested rebar includes rusty rebar, acid preserved rebar and cement chemical compound anticorrosive coated rebar. The Concrete mix design for M25 grade of concrete were used and therefore 18 concrete cube specimens with external projection of steel rod were tested. The various load slip behaviour was studied at the free end finish and loaded end victimization dial gauges. The last word bond stress just like the lowest load worth of 0.025 mm metal slip and 0.25 mm slip was thought of as a result of the usable bond strength of steel rebar’s and concrete. The check results blatant correlation exists between Load at 0.025 mm free finish slip and 0.25 mm loaded finish slip. It had been found that presence of rust and cement compound anticorrosive coating among the steel concrete interface appreciably can increase the bond strength of the order of 20 % and 27 % severally for 16mm diameter bars as compared to rust free rebar. For 20mm dia. Bars has totally different bond strength for rusty rebar’s and therefore the increase in bond strength for coated bars are compared with 2 differing kinds of uncoated bars and rusted rebar’s were determined. It’s over that presence of rust influences in reduction / increase in bond strength hoping on the character of rust at the interface among the initial ages. Application of cement compound coating has been improves the bond strength of the order of 31% – 37 % to satisfies the necessities of Burse Indian Standards code (IS)

Bond behaviour of chemically prestressed textile reinforced concrete

2019 ◽  
Author(s):  
Katarzyna Zdanowicz ◽  
Boso Schmidt ◽  
Hubert Naraniecki ◽  
Steffen Marx
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Crack Width ◽  
Research Programme ◽  
Textile Reinforced Concrete ◽  
Self Compacting Concrete ◽  
Bond Behaviour ◽  
Bond Slip ◽  
Laser Sensors ◽  
Pull Out

<p>The bond behaviour of concrete specimens with carbon textile reinforcement was investigated in the presented research programme. Pull-out specimens were cast from self-compacting concrete with expansive admixtures and in this way chemical prestress was introduced. The aim of the research was to compare bond behaviour between prestressed specimens and non-prestressed control specimens. During pull-out tests, the pull-out force and notch opening were measured with a load cell and laser sensors. Further, bond - slip and pull-out force - crack width relationships were drawn and compared for prestressed and non-prestressed specimens. Chemically prestressed specimens reached 24% higher bond strength than non-prestressed ones. It can be therefore concluded, that chemical prestressing positively influences the bond behaviour of concrete with textile reinforcement and thus better utilisation of its properties can be provided.</p>

scholarly journals Effect of Luting Cement Film Thickness on the Pull-Out Bond Strength of Endodontic Post Systems

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3082
Author(s):  
Khalil Aleisa ◽  
Syed Rashid Habib ◽  
Abdul Sadekh Ansari ◽  
Ragad Altayyar ◽  
Shahad Alharbi ◽  
...  
Keyword(s):  
Bond Strength ◽  
Film Thickness ◽  
Testing Machine ◽  
Resin Cement ◽  
Cement Interface ◽  
Pull Out ◽  
Modes Of Failure ◽  
Fiber Posts ◽  
Luting Cement ◽  
Group A

Optimal bond strength between the prefabricated post/dowel to the surrounding dentin is essential. The present study aimed to analyze and compare the effect of three different cement film thicknesses on the pull-out bond strength of three different prefabricated post systems. Extracted natural teeth (N = 90) with similar root dimensions were acquired. Teeth were mounted in resin blocks, endodontically treated, sectioned at cemento-enamel junction, divided into three groups (A: Parapost Fiber Lux plus; B: 3M ESPE Relyx fiber post; and C: Parapost XP), and stored. Uniform post spaces were prepared for the groups (A and C: Length = 8 mm, Width = 1.5 mm; B: Length = 8 mm, Width = 1.6 mm). Each group (N = 30) was further subdivided into three subgroups (n = 10) based on the size (4, 5, and 6) of the post and cemented with resin cement (MultiLink-N, Ivoclar Vivadent). After thermocycling, the specimens were subjected to a pull-out test using a universal testing machine, and tensile force was recorded (MPa). Digital microscopic evaluations were performed for modes of failure. ANOVA and Tukey-HSD tests were used for statistics. Significant differences were observed for each tested material (p = 0.000). The lowest and highest bond strength values were recorded for Group C (Titanium post) and Group A (000), respectively. Multiple comparisons showed significance (p < 0.05) among all the groups, except for space 1 and space 2 (p = 0.316) for Group A. Most of the failures occurred within the cement-dentin and post-cement interface (Adhesive failures, 73.5%). An increase in the luting cement film thickness results in the decrease in pull-out bond strength of prefabricated posts luted with resin cement, irrespective of the type/material/shape of the post. The serrated fiber posts showed the highest pull-out bond strength compared to the smooth surfaced fiber posts or serrated metal posts. Increased pull-out bond strengths were observed when appropriate post space was created with the same sized drill as the post size.

scholarly journals Bamboo Concrete Bond Strength

2019 ◽  
Vol 9 (1) ◽  
pp. 747-752
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Large Scale ◽  
Tropical Country ◽  
Suitable Material ◽  
Steel Reinforced Concrete ◽  
Pull Out ◽  
Structural Applications ◽  
Bonding Properties ◽  
Bamboo Reinforcement

Bamboo reinforced concrete is expected to be an alternative to steel reinforced concrete as a building material. Steel, when used for construction activities, is energy intensive and causes pollution. In this context, the use of bamboo, which is a fast growing, affordable and ecologically friendly solution; especially in a tropical country like India, is being considered as a suitable material for structural applications. It is potentially superior to steel in terms of its weight to strength ratio. However, the bond strength is a major concern for the bamboo to be a reinforcement in structural composites. The goal of this paper is to investigate the bonding properties of a newly developed bamboo-reinforcement composite in concrete, through pull-out tests. Various coatings are applied to the bamboo to determine the different bonding behaviours between the concrete and newly developed BRC. To improve the bonding at interfacial of bamboo concrete composite; easily applicable, adoptable and economical technology have been developed. The results of this study demonstrate that the bamboo-reinforcement composite develops adequate bonding with the concrete matrix with the hope that the newly developed material could contribute, on a large scale, to sustainable development.

scholarly journals Bond Behavior of Reinforced Concrete Considering Freeze–Thaw Cycles and Corrosion of Stirrups

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4732
Author(s):  
Shuo Liu ◽  
Maohua Du ◽  
Yubin Tian ◽  
Xuanang Wang ◽  
Guorui Sun
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Bond Strength ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Freeze Thaw ◽  
Bonding Performance ◽  
Pull Out ◽  
Steel Bar

In relatively cold environments, the combination of freeze–thaw and steel bar corrosion is a key factor affecting the durability of concrete. The adjustment of the stirrup ratio would change the mechanical performance of surrounding concrete, while the circumferential compressive stress can further improve the bonding performance. Hence, based on eccentrically tensioned specimens, the influence of corrosion of stirrups and freeze–thaw of concrete on bond properties is discussed in this paper. The monotonic pull-out test of reinforced concrete specimens is carried out to study the variation rules of bond strength and slip between steel bar and concrete under the coupling action of corrosion rate, freeze–thaw times and stirrup spacing. Based on the experimental data, the empirical formula for the ultimate bond strength is obtained, and a bond–slip constitutive model is established considering the stirrup spacing, stirrup corrosion rate and freeze–thaw times. Then, a refined finite element pull-out specimen model is established by ABAQUS simulation, and the numerical simulation results are compared with the real test ones, so as to make up for the deficiencies in the test and lay the foundation for further finite element analysis.

scholarly journals Bond Strengths of Geopolymer and Cement Concretes

2010 ◽  
Vol 69 ◽  
pp. 143-151 ◽  
Author(s):  
Prabir Sarker
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Geopolymer Concrete ◽  
Reinforcing Steel ◽  
Test Results ◽  
Reinforcing Bars ◽  
Pull Out ◽  
Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

Analytical and experimental study on shear performance of RCC beam elements reinforced with PSWC rebars: a comparative study

2020 ◽  
Vol 11 (3) ◽  
pp. 53
Author(s):  
Shoib Bashir Wani ◽  
Sarvat Gull ◽  
Ishfaq Amin ◽  
Ayaz Mohmood
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Mild Steel ◽  
Ultimate Load ◽  
Concrete Beams ◽  
High Yield ◽  
Ansys Software ◽  
High Yield Strength ◽  
Steel Rebar ◽  
Deformation Level

Early distress in RCC (Reinforced Cement Concrete) structures in the recent times poses a major problem for the construction industry. It is found that in most of cases, distresses in reinforced concrete structures are caused by corrosion of rebar embedded in the concrete. The HYSD (High Yield Strength Deformed)  rebars which are used to offer excellent strength properties is detrimental to durability due to action of ribs as stress concentrators. Nowadays, concept of PSWC rebars (plain surface with wave type configuration rebars, formerly known as C-bars/mild steel rebar with curvy profile) is emerging to have a compromise between strength and durability. This investigation assesses the flexural behaviour of RCC elements reinforced with PSWC rebars. The flexural performance of RC beams of size 1000mm x 150mm x 150mm reinforced with PSWC rebars at 4mm and 6mm deformation level was studied by conducting test as per IS 516-1959 under four point loading. The performance of PSWC bar reinforced elements are compared with beams reinforced with mild steel rebars, HYSD rebars with spiral and diamond rib configuration to assess the viability of PSWC rebars to replace conventional reinforcement. The test results are validated by numerical analysis with the help of ANSYS software. Totally 15 beams are subjected to flexure test and the performance evaluators are first crack load, deflection at first crack load, ultimate load carrying capacity, deflection at ultimate load, load-deflection behaviour, load-strain behaviour and failure pattern. It is found that PSWC rebars as reinforcement in concrete beams enhanced the ductile behaviour of beams as compared to conventional HYSD and mild steel rebar beams. The energy absorbing capacity has increased significantly for beams reinforced with PSWC rebars when compared with conventional HYSD and mild steel rebar beams. The load-deflection behaviour and failure mode of PSWC rebars reinforced concrete beams were found to be similar to that of high yield strength rebars irrespective of deformation level. The analytical investigation from ANSYS software gave good agreement with the experimental results. It is concluded that PSWC bar has the potential to replace conventional HYSD rebar. Further study needs to be done to optimize the profile level and stirrup locations; and usage with high concrete grade for effective exploitation.

Bond strength of concrete plugs embedded in tubular steel piles under cyclic loading

2006 ◽  
Vol 33 (2) ◽  
pp. 111-125 ◽  
Author(s):  
Abolghasem Nezamian ◽  
Riadh Al-Mahaidi ◽  
Paul Grundy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Bond Strength ◽  
Steel Tube ◽  
Test Results ◽  
Pull Out ◽  
Steel Piles ◽  
Loading Tests ◽  
Cyclic Loading Tests ◽  
Push Out

Investigation of the load transfer of concrete plugs to tubular steel piles subjected to tension and compression and cyclic loading has been conducted at Monash University over the past 3 years. The work presented in this paper reports on the results of the combination of pull-out, push-out, and cyclic loading tests carried out on 15 steel tube specimens filled partially with reinforced concrete with variable lengths of embedment. The pull-out force was applied through steel reinforcing bars embedded in the concrete plug, and push-out forces were applied through a thick top circular plate on the top of the concrete plug. Test results included the cyclic loading, ultimate pull-out and push-out forces, slip of concrete plugs, and longitudinal and hoop strains along the piles for some specimens. The tests clearly showed that average bond strength significantly exceeds expectations and is higher than the results of previous investigations using plugs without reinforcement. The test results also indicated that cyclic loading tests reduced the bond strength due to the accumulation of damage to the plug–pile interface. The push-out and pull-out tests conducted under symmetric cyclic loading demonstrated that slip between the concrete plug and the steel tube increased with repeated loading, and the rate of slip growth increased with an increase in the peak load.Key words: tubular steel pile, reinforced concrete plug, bond, cyclic loading.

scholarly journals An Experimental Study on Effects of Corrosion and Stirrups Spacing on Bond Behavior of Reinforced Concrete

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1327
Author(s):  
Konstantinos Koulouris ◽  
Charis Apostolopoulos
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bond Strength ◽  
Mass Loss ◽  
Corrosion Damage ◽  
Ongoing Research ◽  
Average Width ◽  
Concrete Cracking ◽  
Bond Behavior ◽  
Pull Out

The current experimental study consists of part of an extensive and ongoing research on bond behavior of RC elements damaged by corrosion, focusing on stirrups spacing effect on bonding. For this, RC specimens with different cases of stirrups spacing were casted. Accelerated corrosion was induced in order to simulate the slow process of nature corrosion on RC specimens and the corrosion damage was estimated in terms of mass loss of steel bars and average width of surface concrete cracking. Subsequently, pull-out tests were carried out to examine the bonding resistance between steel and concrete. The study indicates the great influence of density of stirrups on the percentage mass loss of the embedded reinforcing bar, accompanied by width of surface concrete cracking, as well as on bond strength between steel and concrete. The results of bond stress–slip curves show that the densification of stirrups plays a significant role in bonding, leading to higher bond strength values and delaying the degradation of bond loss as corrosion damage increases. However, it becomes apparent that, although the densification of stirrups (Φ8/60 mm) result in the full anchorage of steel-reinforcing bars, it may be inappropriate, since it can lead to a substantial increase in costs and a rapid rise in corrosion rate, due to potential increase. Furthermore, the recorded values of relative slip at bond strength are between 1 and 3 mm, regardless of corrosion damage or concrete cracking, which depends on the ribs geometry and crushing of concrete in front of them. To conclude, the results of the present manuscript indicate that the increase in transverse reinforcement (stirrups) percentage plays a key role in the durability of reinforced concrete elements and in bond strength maintenance between rebar and concrete.

Relined Fiberglass Post: Effect of Luting Length, Resin Cement, and Cyclic Loading on the Bond to Weakened Root Dentin

2016 ◽  
Vol 41 (6) ◽  
pp. e174-e182 ◽  
Author(s):  
NC de Souza ◽  
ML Marcondes ◽  
DFF da Silva ◽  
GA Borges ◽  
LH Burnett Júnior ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Bond Strength ◽  
Laser Scanning ◽  
Testing Machine ◽  
Resin Cement ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Pull Out ◽  
Anterior Teeth ◽  
Bond Interface

SUMMARY This study evaluated the effects of luting length of the post, the resin cement, and cyclic loading on pull-out bond strength of fiberglass posts relined with composite resin in weakened roots. The canals of 80 bovine incisors were endodontically treated and weakened with diamond burs. The teeth were randomly divided into eight groups (n=10) according to the luting procedures of the relined fiberglass post (RFP): In groups 1, 2, 3, and 4, the RFPs were luted with RelyX ARC, and in groups 5, 6, 7, and 8 they were luted with RelyX U200. In groups 1, 3, 5, and 7, the RFPs were luted at a length of 5 mm, and in groups 2, 4, 6, and 8 they were luted at a length of 10 mm. Specimens from groups 3, 4, 7, and 8 were submitted to cyclic loading. Specimens were subjected to a pull-out bond strength test in a universal testing machine. The results (MPa) were analyzed by three-way analysis of variance and the Tukey post hoc test (α=0.05). Six human upper anterior teeth were used to analyze the bond interface by confocal laser scanning microscopy (CLSM). The pull-out bond strength of RFPs luted with RelyX U200 was statistically higher than that of RelyX ARC. Cyclic loading influenced the bond strength only for the luting length of 5 mm. CLSM analysis revealed the formation of resin cement tags for both materials. Luting length is an important factor in retaining RFPs in weakened roots when they are subjected to cyclic loading, and RelyX U200 resulted in greater bond strengths to the root canal in comparison with RelyX ARC.

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